Field of the Invention
The present invention relates to a saltcore for die-casting with aluminum and a manufacturing method thereof, and more particularly, to a saltcore and a manufacturing method thereof capable of reducing shrinkage while satisfying strength during casting by including at least one cation of K+, Na+ and Mg2+ and at least one anion of and CO32−.
Description of Related Art
A casting process uses the flow of a liquid and is a kind of material processing method of putting a molten metal material into a prepared mold and filling and coagulating the mold, and various methods have been used according to a shape and an injection method of the mold.
Such a casting process has an advantage of forming a complex shape by using a meltable material in only one step. The casting process consists of a mold manufacturing process, a melting process, an injection process, a mold separation process, and the like. In the mold manufacturing process, the mold needs to have a shape and a size appropriate for a desired casting so as to be manufactured and have a proper margin for shrinkage of a solidifying material. In the melting process, the metal is heated at the appropriate temperature to form a liquid, and then a hydrogen gas furnace in the molten metal needs to be removed. The injection process needs to be designed to prevent the solidification shrinkage during solidification while minimizing generation of eddy current during injection. Thereafter, the mold is separated, and after separation, the casting process is finished through the processes of cutting, washing, heating and inspecting an injection port and a spout hole.
On the other hand, a shape (material) inserted into the mold to form the internal shape of the casting is called a core. The core is used for manufacturing a hollow product and the core needs to have sufficient mechanical strength to withstand heat and pressure of the molten metal and maintain the shape during casting, and simultaneously, needs to be relatively easily broken or dissolved into other materials to be easily removed from the cast article after die-casting.
Sand or thermosetting resin is generally used as a material of such a core. In the case of method of using the sand, that is, a sand core, the sand forms the core with a binder, and after casting a desired structure around the core, the binder and the sand that support the core are removed. In the case of a method using the thermosetting resin, a foam is used as a material of the core. However, methods using the sand or the thermosetting resin have been pointed out to cause environmental problems. Furthermore, in the case of the sand core, there is a problem that the sand core may not be realized when a reverse gradient shape exists in the cast article. In order to solve the problems, the material of the core used for casting is made of salt, but in the case where a saltcore in the related art is used for aluminum casting, there is a problem in that the strength to withstand the impact of molten aluminum is insufficient or the shape of the cast article is deformed due to shrinkage of the saltcore during casting.
In order to solve the above-mentioned problems, the present invention proposes a saltcore for aluminum casting capable of reducing the shrinkage while maintaining the strength of the saltcore in the aluminum casting process, and a manufacturing method thereof.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.